1. Field of the Invention
The present invention mainly relates to an input apparatus used for the operation of various electronic devices in an automobile.
2. Background Art
In recent years, many drivers of an automobile uses his or her fingers to operate an input apparatus such as a switch attached in the vicinity of a steering wheel, while still holding the steering wheel, to operate an electronic device such as an audio device or an air conditioner. In order to realize the application as described above, an input apparatus is preferred that is free from an operational error and that can be operated easily.
The conventional input apparatus as described above will be described with reference to FIG. 8 and FIG. 9.
FIG. 8 is a cross-sectional view illustrating a conventional input apparatus. The following section will describe the configuration of input apparatus 7 with reference to FIG. 8. Case 1 has a substantially box-like shape and is made of insulating resin. Operation body 2 is also made of insulating resin. An upper face of operation body 2 has display section 2C. Display section 2C is formed so that transparent or light-colored translucent section 2B having a predetermined shape (e.g., character, symbol, picture) for example is exposed out of non-translucent section 2A colored with black for example. Non-translucent section 2A is formed by a laser processing or a two-color molding for example. Operation bodies 2 are attached in opening holes of the upper face of case 1 so as to be movable in the up-and-down direction.
Switch 3 is a push switch for example that is formed so as to be turned ON or OFF when operation axis 3A protruding to the upper side is moved in the up-and-down direction. Operation axis 3A is abutted to projection 2D at the lower face of operation body 2.
Wiring substrate 4 has, at the upper and lower faces thereof, a plurality of wiring patterns (not shown). Switches 3, light-emitting elements 5 such as light-emitting diode, and control section 6 such as a microcomputer are mounted on the upper face of wiring substrate 4. Wiring substrate 4 is structured so that switch 3 and light-emitting element 5 are connected to control section 6 via the wiring pattern. In this manner, input apparatus 7 is configured so that case 1 covers wiring substrate 4 and control section 6 for example.
FIG. 9 is a front view illustrating a steering wheel including a conventional input apparatus. As shown in FIG. 9, input apparatuses 7 are attached to left and right spokes 9B sandwiched between steering wheel 9 and pad 9A accommodating the center air bag or the like so that operation bodies 2 are provided at the front faces of left and right spokes 9B. Control section 6 is electrically connected to an electronic circuit or an electronic device (not shown) of a vehicle via a connector, a lead wire (not shown) or the like.
When a driver uses the configuration as described above to extend a thumb for example, while holding steering wheel 9, to depress and operate operation body 2 on which a function that the driver intends to carry out is displayed, projection 2D at the back face of operation body 2 presses operation axis 3A to turn ON or OFF switch 3. Then, an electric signal is outputted from control section 6 to an electronic circuit or an electronic device of the vehicle to control various devices provided in the automobile (e.g., to increase or decrease the volume level of an audio device or the temperature of an air conditioner).
When a headlight or the like is lit to illuminate the periphery of the vehicle at night for example, control section 6 controls light-emitting elements 5 to emit light. This light illuminates operation body 2 from the lower face. Light passes translucent section 2B and illuminates display section 2C of the upper face. This allows, even when the periphery of the vehicle is dark, the driver to visually recognize the characters, symbol, picture or the like on display section 2C to easily identify or operate operation body 2.
In other words, the driver can, without separating his or her hand(s) from steering wheel 9 on which input apparatuses 7 are attached, extend only a thumb for example to operate any of operation bodies 2 to control a device in the vehicle, thus realizing an easy operation of the device while driving.
A technique regarding the above-described conventional input apparatus is disclosed in Japanese Patent Unexamined Publication 2005-347193 for example. In the conventional input apparatus, operation bodies 2 have functions for operation displayed by display sections 2C. When the periphery of the vehicle is dark, display sections 2C are illuminated by light-emitting elements 5. This conventional structure however had a disadvantage in that operation bodies 2 arranged to have a similar shape tended to cause an operational error such as the depression of a wrong operation body.